Z2M ethernet coordinator wont connect to LAN any more even after reset

i have bought my third zigbee ethernet coordinator
ZB-GW03-V1.4,
https://www.aliexpress.com/item/1005005959454155.html

i have 2 same ones which i have used successfully until today with my HA
I managed to configure this 3rd Z2M instance and it worked for 1 full day (i did have issues with at first - see post Help! zigbee ethernet g/w wont boot after wrong configuration ) but it was solved

then it disappeared from my LAN network, cant ping it and it wont show in the router DHCP client lists
i reset it to factory and tried again - it just wont show on my router

the red/green leds keeps blinking (cant upload video here)

i dont see its default Wifi network as well

any ideas?

@francisp your insights are welcomed!